Coatings are typically applied to substrates to provide protective and/or decorative qualities. One effective technique for applying coatings includes an electrocoating process, which typically involves depositing a composition onto an electrically conductive substrate with an applied electrical potential. Early attempts at commercial electrocoating processes used anionic electrocoating processes, where the substrate being coated served as the anode. However, cathodic or cationic electrocoating processes have become increasingly popular, and today, are the most prevalent methods of electrocoating.
One desired property of coatings is corrosion resistance. The use of coatings exhibiting good corrosion resistance prolongs the functionality and performance of the coating composition and the underlying substrate. This is particularly important for coating compositions applied to surfaces or substrates that are used in highly corrosive environments, including, for example, in the heavy machinery industry.
Components or parts in the heavy machinery industry, as well as in other industries, are often laser-cut, stamped or formed, and conventional coatings do not always coat the edges of such metal parts sufficiently to provide optimal corrosion resistance. As a result, these components or parts suffer from edge corrosion and subsequent failure. The heavy machinery industry now attributes more than $250 million in annual claims to corrosion failures, and specifically to edge corrosion.
Accordingly, there is need for an electrocoating composition that exhibits good corrosion resistance, and especially good edge corrosion resistance.